Test your knowledge of lasers
1. Which of these people use lasers while working?
Orthodontists
Plumber
Surgeon
all of the above
2. All lasers must have which of the following
a medium
a light source
both of the above
none of the above
3. How many classifications of lasers are there.?
3
2
4
none of the above
4. Which part of the human body is most vulnerable to laser radiation?
skin
eye
brain
ears
5. What color is laser light?
always red
red or green
any color depending on what type of medium is used
none of the above
6. Which of these materials are acceptable mediums?
gases
solids
liquids
all of the above
Answers: 1b, 2a, 3d, 4b, 5a, 6a
1. What does LASER stand for?
Latent Amplification of Stimulated and Elliptical Radons
Latent Absorption of Specified Elliptical Radons
Light Amplification by Stimulated Emission of Radiation
Light Absorption by Simulated Emission of Radiation
2. What particle plays the major role in the process of lasing?
Electron
Neutron
Proton
Krypton
3. What do you call an atom whose electrons have reached a higher
energy state?
Energized state atom
Excited state atom
Lasing atom
Radiative atom
4. When an electron drops down from a higher energy state and
recombines with a hole, what is produced?
A gamma ray
Nothing, they cancel out.
A current
A photon
5. Laser light has many features different to ordinary incandescent
light. Which of these is NOT one of them?
Coherent
Intensely focused
Monochromatic
Diffuse
6. What requirement needs to be met before a medium can begin to
'lase'?
Threshold voltage
Population inversion
Equal density of states
100% slope efficiency
7. What is the minimum number of energy levels needed for lasing?
1
3
2
4
8. The wavelength of the laser light is a direct relationship with what
feature of the medium?
The density of excited state atoms
It has nothing to do with the medium
The amount of energy levels in the lasing process
The energy gap between the excited state and ground state
9. What is NOT a form of laser?
Dye
Semiconductor
Creatine
Gas
10. In what decade was the first laser built?
1980's
1950's
1960's
1970's
1. What does LASER
stand for?
Your Answer: Light
Amplification by Stimulated
Emission of Radiation
This term was coined in the 60's
after the MASER - Microwave
Amplification by Stimulated
Emission of Radiation.
89% of players have answered
correctly.
2. What particle plays the major role in the process of lasing?
Your Answer: Electron
When a photon (a light particle) hits an atom, an electron absorbs the energy
from that photon and moves to a higher orbit around the atom.
When this atom then encounters another photon exactly the same as the first
one, the electron moves back down to its original position and releases the
energy it gained in the form of another photon.
Thus TWO photons are now present, hence the amplification part of laser.
Krypton is a noble gas, not a particle. Protons and Neutrons form the nucleus
of an atom.
71% of players have answered correctly.
3. What do you call an atom whose electrons have reached a higher
energy state?
Your Answer: Excited state atom
When an electron reaches a higher orbit after absorbing a photon, it is said to
be in an excited state. Only excited state atoms are useful to the lasing
process.
76% of players have answered correctly.
4. When an electron drops down from a higher energy state and
recombines with a hole, what is produced?
Your Answer: A photon
As mentioned earlier, when an electron moves back down to its original
position, its extra energy is released as light (a photon).
71% of players have answered correctly.
5. Laser light has many features different to ordinary incandescent
light. Which of these is NOT one of them?
Your Answer: Monochromatic
The correct answer was Diffuse
Coherent: light waves that are "in phase" with one another.
Monochromatic: of one color. All laser light is of one wavelength at a time.
Notice the absence of a white laser (mix of wavelengths).
Diffuse: light that travels in many directions. All laser light travels in one
direction, not like a light bulb which travels in all.
Intensely focused: the light is very directional. A laser light has a very tight
beam and is very strong and concentrated. A flashlight, on the other hand,
releases light in many directions, and the light is very weak and diffuse.
71% of players have answered correctly.
6. What requirement needs to be met before a medium can begin to
'lase'?
Your Answer: 100% slope efficiency
The correct answer was Population inversion
In a laser, there are two important levels, the excited state and the ground
state. For lasing to occur, there needs to be a greater amount of electrons in
the excited state than in the ground state, and this is given the term population
inversion.
40% of players have answered correctly.
7. What is the minimum number of energy levels needed for
lasing?
Your Answer: 3
Although 2 states would be theoretically possible, in reality its not. While
some electrons will be trying to get to the excited state, some will also be
dropping back down. These processes interfere with each other so much that a
third level is needed. Electrons move up to the excited state, they drop down
to a sub level, and then to the ground state, thus avoiding the clash.
38% of players have answered correctly.
8. The wavelength of the laser light is a direct relationship with
what feature of the medium?
Your Answer: The density of excited state atoms
The correct answer was The energy gap between the excited state and
ground state
The energy gap between the excited state and the ground state determines
how much energy the electrons gives away when it drops down. This energy
as mentioned then becomes a photon. The greater the energy of this photon,
the smaller its wavelength.
55% of players have answered correctly.
9. What is NOT a form of laser?
Your Answer: Dye
The correct answer was Creatine
Creatine is a substance used in bodybuilding to increase the amount of water
molecules muscles hold.
45% of players have answered correctly.
10. In what decade was the first laser built?
Your Answer: 1960's
Schawlow and Townes, both researchers at Bell Labs, invented and patented
the theory of a laser in the 50's. It wasn't until 1960 that they actually built
one, using a ruby.